DocDiff compares two files and shows the difference. It can compare
files word by word, char by char, or line by line. It has several
output formats such as HTML, tty, Manued, or user-defined markup.

WWW: http://www.kt.rim.or.jp/~hisashim/docdiff/
Author: Hisashi MORITA <hisashim at kt dot rim dot or dot jp>